Regulation of the synthesis of specfic proteins in the uterus of the ovariectomized mammal by estradiol-17Beta and progesterone will be investigated. Most of the research objectives proposed can be accomplished by high-resolution protein mapping of double-labeles proteins obtained from uteri of hormone treated rats. The specific aims are summarized as follows: 1. Further characterization and rigorous testing of the functional identities reported for estrogen-induced proteins of the at uterus, that have thus far been identified by protein mapping. 2. An investiation of the functional identity of the third estrogen-induced protein that has also been mapped. 3. Identification and characerization by protein mapping of all additional estrogen-induced prteins of the rat uterus. 4. Determination of the presence and quantiative distribution of the estrogen-induced proteins (i) in both target and non-target tissues of estrogen in the rat, (ii) in various cell types of the rat uterus, and (iii in uteri of species other than the rat (mouse and rabbit). 5. An investigation and delineation of the effects of progesterone on the regulation of "new" and/or "old" proteins in uteri of both estrogen-primed and unprimed rats. The various cell types of estronge-progesterone treated uteri will also be examined similarly. 6. Development of several immunological assays for the study of estrogen- and progesterone-induced proteins. This will include attempts to producoe monoclonal antibodies for these proteins. 7. Subcellular localization of various hormone-induced uterine proteins. This will be assessed by immunological and the high-resolution electrophoretic techniques. The research proposed will provide new data permitting the formation of hypotheses concerning the appearance and roles of cytoplasmic proteins, induced or modulated at the subcellular level by estrogen and progesterone. Little is known of how steroid hormones change the cytoplasmic population of specific proteins of the mammalian uterus in "preparation" for implantation. Such information is important with respect to mammalian reproduction and population control.